A hardware accelerator is disclosed for performing a computational operation in a cryptographic application comprises one or more addressable computational blocks and a plurality of addressable register blocks. A bus is used for data exchange between the blocks in the form of read-from-bus operations and write-to-bus operations in the course of performing the computational operation. A controller for controlling the data exchange performs a block addressing operation using a respective pre-assigned first address of the blocks for addressing the one or more of the blocks involved in a write-to-bus operation in the data exchange. The controller performs a dummy-addressing selection operation to select one or more of the blocks for a dummy addressing operation and a dummy-addressing operation of the selected one or more of the blocks for dummy-addressing the one or more of the selected blocks in the write-to-bus operation.